Have you ever thought of starting a few contests on the forum ? Here are some ideas:
.Best new member (monthly)
.Most helpful poster (weekly and monthly)
.Most original thread starter (weekly)
Please, add up... if the thing's done with the right spirit, we could have negative nominations, too. For instance, I could get this month's "award for dumbest suggestion"
(well, let's make it this week's
The winners could get.... well, community recognition of course, what else ?